Electric plug and socket



Aug. 20, 1940. H. E. ROBINETT 2,212,075

ELECTRIC PLUG AND SOCKET Filed Jan. 26, 1939 lNVE NTOR ATTORNEYS 32 fiffi? 22 La Patented Aug. 20, 1940 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to an electric plug and socket and has for an object to provide a plu and socket one of which is equipped with a groove and latch bars and the other of which is-equipped with hooks adapted to enter the groove and engage underneath the latch bars when turned slightly after the parts are assembled so that ease in assembly and disassembly will be promoted while at the same time accidental disengagement will be positively prevented.

A further object is to provide a plug connector of this character which will be formed of a few strong simple and durable parts, which will be inexpensive to manufacture and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claim without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a front elevation of a wall socket constructed in accordance with the invention.

Figure 2 is a longitudinal sectional view of a plug constructed in accordance with the invention.

Figure 3 is a longitudinal sectional View taken on the line 3-3 of Figure 1.

Figure 4 is an end elevation of a pronged socket for use in connection with a conventional type' wall outlet.

Figure 5 is a longitudinal sectional view taken on the line 55 of Figure 4.

Figure 6 is a longitudinal sectional view of a socket having a screw tight outer terminal.

Figure '7 is a side elevation of the plug shown in Figure 2 with the cap assembled.

Referring now to the drawing inwhich like characters of reference designate similar parts in the various views, l designates a socket of substantially cylindrical contour having one end closed by a wall H and having'the opposite end open. The socket is provided with an axial bore l2 provided near the open end with an annular groove l3 in which is countersunk a ring terminal 14. A binding post to receive a conductor wire is secured in the face of the wall H and iselectrically connected to the ring terminal through the medium of a conductor wire 16 which is imbedded in the material of the socket. A second binding post ll adapted to receive a circuit wire is secured to the face of the wall II and is provided with a spring bar l8 which is exposed in the bore l 2 at the center of the wall I l and forms a center terminal.

A wall plate I9 is secured to the open end of 1 the socket in any preferred manner and forms an integral part of the socket. The wall plate is provided with an annular groove 20 concentric with the axis of the socket and which extends into the socket. A plurality of latch bars 2! are formed integral with the wall plate and are of less depth than the depth of the groove 22. These latch bars extend across the socket at equally spaced intervals.

The plug 22 is provided near its outer end with an outwardly directed flange 23, which, when the plug is inserted in the bore of the socket, overlies the groove in the socket. Hooks 24 extend outwardly from the'fiange and have their shanks 25 arranged parallel to the axis of the plug. These hooks are adapted to enter the groove 20 of the socket during the insertion of the plug into the socket. The bills of the hooks are extended in a direction to engage underneath the latch bars 2| when the plug is turned slightly after its insertion into the socket.

The plug is provided with an exteriorly threaded shell 26 which receives the interior threads of a cap 21 which houses screws 28 and 29 adapted to receive circuit wires. A center contact 30 is arranged on the end of the plug and is electrically connected to the screw 29 through the medium of a wire 3| imbedded in the material of the plug. A spring metal contact 32 is arranged in a recess 33 formed in the side of the plug and is connected to the screw 28.

In Figures 4 and 5 there is shown a modified form of socket 34 having a pair of prongs 35 and 36 adapted to be inserted in a conventional type wall outlet. The prong 35 is provided with a center contact 31 arranged in the bore 38 of the socket. The prong 36 is electrically connected by a wire 39 to a ring contact 40 which is countersunk in the wall of the bore concentric with the axis of the socket.

The socket is provided in the end opposite the prongs with an annular groove 4 l. Latch bars 42 are formed integral with the socket and have a thickness less than the depth of the groove. These latch bars extend across the socket at equally spaced intervals. The hooks 24 of the plug enter the groove of the socket during the insertion of the plug into the socket and the bills of the hooks engage underneath the latch bars when the plug is turned slightly after its insertion into the socket.

In Figure 6 there is shown a modified form of socket 43 having a screw outer terminal 44 and having a center terminal 45 provided with a spring contact 46 which enters the bore 41 of the socket. The outer contact 44 is electrically connected through the medium of a wire 48 with a ring contact 49 which is imbedded in the Wall of the bore concentric with the axis of the bore. The socket is provided with an annular groove 50 as heretofore described concentric with the axis of the bore and located in the end face of the socket at the open end thereof. Latch bars 5|, as previously described, extend across the socket at equally spaced intervals to receive the hooks 24 of'the plug when the plug is inserted in the socket and turns slightly after its insertion into the socket.

From the above description it is thought that the construction and operation of the invention will-be fully understood without further explanation.

What is claimed is:

An electric plug and socket comprising a substantially cylindrical socket having one end closed and the opposite end open, there being an axial bore in the socket provided near the open end with an annular groove, a ring outer terminal seated in said groove, a spring bar in the closed end of the bore forming a center terminal, a wall plate on the open end of the socket forming an integral part of the socket, the wall plate being provided with an annular groove concentric with the axis of the socket and extending into the socket, a plurality of latch bars formed integral with the wall plate and extending across the groove in the wall plate at equally spaced points, a plug provided near its outer end with an outwardly directed flange adapted to overlie the groove in the wall plate when the plug is inserted in the socket, hooks extending outwardly from the flange and having their shanks arranged parallel to the axis of the plug, said hooks being adapted to enter the groove of the wall plate and socket during insertion of the plug into the socket, the bills of the hooks extending in a direction to engage underneath of the latchi bars when the plug is turned slightly after insertion into the socket, a center contact arranged on the end of the plug adapted to engage the spring contact of the socket, and a spring outer contact disposed on the side of the plug adapted to engage said ring terminal.

HARLEY E. ROBINETT. 

